SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6040c5f151f17b8eda2d841a55231f031389af197d7080ab86022e511138bcd7' 
  AND token = 'GTk6n8bOrVZwEfPfHzOrI2gC88o9Y4ItM9tGj17AOuo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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