SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d2e62e5440212fb717ea02247917fd3d638551297c5db33404816f4497f4bb2' 
  AND token = 'XxEm9a6CR/DMkhUccFT5OiDLmnnYRErhsIQIJazFL6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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