SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a80f1a56f635b1882359bd1fdbd292463294b47d1560619fe186492aa1cad28' 
  AND token = '80cp2tUJPeqvZNrQ1YFigTJFsOBRp80sUW0CPy6SKtU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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