SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfcfc9f6fa42da118321c1f080078b4417196a2f63ecc908cd58506b85a6021b' 
  AND token = 'jdgMoy+muGz1KnR3w4oZQFbU7mTJow5o/lvD8rX/pfE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}