SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c069850a0de640978855b080232ca025b96bfdd757ddccca72c387d88ed037b9' 
  AND token = '7d4OT5n4oDiCH6j8//SeWsVR3Agd0nNfcSfFW07gyTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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