SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6346a99d42160c42ca6fe988ff0c9a650995615ef18dadb55995b35353f15e32' 
  AND token = 'VzizeWKZ/v8PssEMgy9bYwFFGvVQwNSRpfQIdixlCBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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