SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c165692557cc529a865f33353fe16ac707f92e53b308835ffcc279b6289513c' 
  AND token = '7twYbmmT+MZtPFP/Z2jDSmfzIl1CXcj5vG9lAp47RuU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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