SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef802aeac3cc1751cc4d588991f60cfeafc76a27c54ee700869f607b250f6bf9' 
  AND token = 'eL6pl7f/JiPV//etR6WFKSgNQE5aJcMTbx++/ZomcJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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