SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b7972e77fced91d2108ff4f871246bb9a310e66c75172bb35b10977d78a4571' 
  AND token = 'sUhcxIUNlO4mItJ7olqU1hqkiyJKQHC9GLpbdz29kV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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