SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0043b556e33f3038d777eaf6b3aec220265251cb04aa8b397a20946a60511a86' 
  AND token = 'VJVNv2R9Y+9ZjwTYNySxyD5FrChstJSd/RoFjlT1MfA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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