SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67451bdf20044a54c76283e79aa8d8755cdcb6309edd3ad79b89fa0642aca7b2' 
  AND token = '4XpxIi59Kjeu36tPAE3ejbGyTekfRjQjl6i5mFKyZIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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