SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b381d44c2f352b0516904f4379de5962995f886aa7df82bb17eeb2b60fa14b1' 
  AND token = '6spMw19nF5+BuCjMHAAO7zn70VFURdydRZTYKSoRY5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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