SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1865948ac728409e27600d04de45edeb2314f7074638e13cb5ad99281e101316' 
  AND token = 'TIcp6+z92duNcAOzCawmTgqUOlMPdlEJKBTfAUG3Tv0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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