SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a79aebdacde91342c9d1b56fb2c5e866ada6dd4df0082bc24dc9f1f5ddcdcb1b' 
  AND token = 'fVqpD77r/p+SjLFLOjg3VPkB+xe9HxdhOJCZsnlwBnU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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