SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75432d6b4126964e2f89892fb031a71181da44f1d43462da746c40c2f4b67aa4' 
  AND token = 'SK0YQ2jz7chlXZeO1D9XJ1t1VP6cKBU6bw9Ls6Ex4L4=' 
  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"
    }
  }
}