SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83e7490d0147d367688ca22599cb59425b3235ed61d9296342bd9f004cdc4319' 
  AND token = 'q1vOKZuff/GNUTrAEqy+YATXQxizeAaVGj03lSw7MKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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