SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2bf3e8ff100eaa115dd8a3b88baf01e367dd0931eef9720ae506c948d913758' 
  AND token = 'mhZjjbpm6a0SvPHDo6lFz/7pf744oljI4iaTBR6Wduw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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