SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54e3f438d3abdfcaad9953060b59d9107cfdf52da22aaa56e840fb62616e2d16' 
  AND token = 'LrZ3pMrZFx7M5kSYONf77AFMEuBefMw4LNqPyRcF+0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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