SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec59a91fc56f5dd4dccb600f425b43e466b2636861e30db779dec4b621f8b74d' 
  AND token = '7NpQOm9lYCvUwhExuXe5xUDMELD+/W78CBPcaGAz6VM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}