SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3467d99666054dd4335d6b554f43e5be7471411ce5ec71a1021b691db7e4e9ed' 
  AND token = 'hspDBBVEXO7dBXJ+kUEG9lyFB+EnFmGQwuPPoU/uLdo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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