SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '483407fa01f33e27ae514d3a2f329aaa5e009a85b5c28395e0cd4de2d72f4794' 
  AND token = 'hRS06lDpWPlD9hxy0UGt2aUzsX7bascVWoo6pJesddA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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