SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54a00a376e55ef4d0185bd1ba76882fbeaf4bcd99fcf935cc6d07bb0b8ecf50e' 
  AND token = 'GRKgwl1klKbgfS8rzzbClqeQW8buDUlLUU0GmYccoFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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