SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '307604d179699fa98a2bdb1021ce911df8ff81d2317d9429aa31218686990e50' 
  AND token = '2D907R62GjICrJm1Xw886GXwMPT4CcdDQxvsEgv/6+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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