SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4e8ad18745abfbf2b73c92410b92d3381c9bfac42beb5080e572c3cbd75af28' 
  AND token = '8SkyyyOpQ3+3GraQ00vDLWI4hEh4EKQ2m1Glwnpizww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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