SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '484eae6b84f6a3c7b25f66d4175f4ebfbde21202503a78a7d31a1cceb644f3fd' 
  AND token = 'hyWHtlwxHbaBRdiHEovG2OIgffZltsydxon48k6gahY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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