SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5975524045ac69c79329369b3e105f2cf5afe8579ac89b71fbb8242d1ad038c8' 
  AND token = 'MHD0SpVeOlPSBBTCAMREcMmXUeKwZ+AFN+gDcUBod9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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