SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bf2a1e999e17a94d230485563fbdab4996e2aed9a04630d899e1527a9ce5634' 
  AND token = 'ffq7OzjXTpmbsxIysijQ7LSnwMdnOg0MxnXzudyuPN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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