SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '775aa0a2ece7ffbbd1056741137499f465fcced49705873bf8958f90fa292e0e' 
  AND token = 'vwtBXU+KjSRTFkh9XiPxG/vSMwnwRBSVhMj8nU7b6kU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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