SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96973132b0b1cc99461d114225ec52919af83d324a096cd6df29a04bf582f587' 
  AND token = '0dYOlqlj+yLJaNU7GGSt0g/Ix5kVShBaHDSaSfiOfUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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