SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da8d06b80cc1a0a2a2f1490c99a9d5451676e76af072bbe6c8e543c4321820f0' 
  AND token = '2IbmOcCfkvmEcfIM77w8+7soMRPXyoMGOWe7MBb/aGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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