SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cea553bf495dba4b045acb1133b0402c786fd5274244f6c4ca19e67547af25ba' 
  AND token = 'oIXY264xQlURUW25TfdY9Yml2MiVz3up0uutBwqZGt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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