SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6366b13f8c8582d48137941baceb4b225f2f784bd8aacb31cd697197b89ddd30' 
  AND token = 'iCCVegbUx7XGjdvw0dYcegEkR7ybAWAM9V/j6ex+wV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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