SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9937c1126f23d675e64c1d7d6158b03699b5fb48b4bef3366de61b37a3fdc8fb' 
  AND token = 'GiGbhYWidownY+fMAjQCQaGly70z3HyJ7VZAzSBXYoA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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