SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a25719c612a076079fe939fb32909bc38266bf4ba73dd5d794d2c4425f470dbf' 
  AND token = '4b28uVl/NmoBKforvwYSgGAbl6/SVTIKIaTCnxCDLes=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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