SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '80091bc781f15e88e0ad799a479e13fa4721f1014f11bc70569ab3f9efcdbb50' 
  AND token = '2xLPrzH8rAQtxNKtsKUUxTGXV7MkC2duTm76qM7ljHM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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