SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b6f880c81d4b7944f3bb691c4619de0946476288d93ee793e87a208d276665d' 
  AND token = 'P81kesAp0SNJNcq3Q44aaYXry0+MKHIjJt67wxAE9c4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00077

JSON explain

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