SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8582f52be2e285699a06854b610ce5847b8ce7df0196ff11f4d2e04cfe21b6e' 
  AND token = 'XCpbLoqYlfhDnWDkioYJRpCPMbUzwdHh8jBFGSwBD4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}