SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8dde8a3a0e386cb4ce67617ca25753425f469f40e41975d786bb57846973315' 
  AND token = '67TWiWMHthupHcAaPfRVKVHvlGdUeK7FEeGX5xPrTx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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