SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '389705bfbb1fe1100061076abacc855137fcd0ea11a44e62377d178b21ebd47e' 
  AND token = 'OX3cTDvFhp3wdDMXZzunGYDwM5MQP6fEQg+CByJySVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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