SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c353bb292563b790c2383ed818184a4d7895482201278fa5a11d839e45b0198f' 
  AND token = 'LANqF7ufhuyxUhPUnQpqvw/zXr1LS0RtzvWcp0QHj28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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