SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6e2eb02c6d7638d1d01c2b4d474d46e00719e79678c9ff42190e3aa13356b8c' 
  AND token = 'lGRz2K9Vl7yK8gwVzjIhQi4+nRzMNxAsvGxXKxjP5Fw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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