SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bc80765392de430d6aa04eb535deb505c83646278370c69f758a960656d4bb7' 
  AND token = 'gJ5rzxwTxVHxXJL1bT/mJB55AUj1B8Zik8MpMiOfyJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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