SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d26828d77f8331d71c73bcb44035312c6dcdf27253cabe8ecddc4f4ed567876' 
  AND token = 'h7M4o5GhjjokA41VliKcCmxQ+YmCthjK4DQLCBmHSjE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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