SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f2c904c9fc04a14dbefde489a67deb32693f1102188de7ee901944e71afdf4c' 
  AND token = 'sjtTDKjkPR+tCqtdGAYftsmYT4JwlUSJ3tdjRtGiRdg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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