SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '935689fb2a2514c42ca352faa7c74252f417710a75a3a5e7728374d2efce6613' 
  AND token = 'bYjOAkD5IGWHwZjGEUZ61BrTHtK921avsGfb2uIaoIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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