SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7644b32791c8191e1e1547856282ca519c06fc25c9112dc3162a5e71cdc4023a' 
  AND token = 'X4cXtvlcIMSbZnFVqMW0EzLZIQGVlLDDhRTg/dHN5x8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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