SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cbdfddbd61df09d473ae04ce7b3510b20369c7388bbeddc14ae88da1592f1a9' 
  AND token = 'DewRWvfTGePpYRR7/MNzsQIxli1hHxaer0qJkLZgiQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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