SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7e60e91ae831763357cb38790d4359a1cca9356333e053b4357c55b1ea146de' 
  AND token = 'KSJxWyl+MVREgKHROk+lbQTfe3cWGHvB2Qj/heDVF+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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