SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f635d69045c15829c5d0178b5ac710688b870298f94f7892dc05dae25b450b89' 
  AND token = 'ml68YeNu1pe6DJ21gxoHgU7/SqQE4U3TpICIox4uAXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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