SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5309be01434b494c0ea6d4d4a2ddc52f69058be809fff8ea49311172ab3d26f' 
  AND token = 'aMoaGwDJW0XkY6T9Uvb0fpZHMbBRJUvA4qmwhAEye1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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