SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2deb15e8b2be8465a7acf2b48df12e18cfe3c03ff510db085b72b20b4d88a968' 
  AND token = 'PZiUy9WNDH8vG4HiJbdlox9lQ8/IkYzGRR/6i2bFgRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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