SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '154a1093de4a281debaaf6e7019af5d48460251a19aa2c45add6a2295c8a631f' 
  AND token = 'qXIZsx10IzWLNeFZDyFMUkwJej5LjqO553nKOrO+CcY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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