SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '767c4c8567b8e6439b3c95c598c21ebf99a27901c9ee8cc7c4f8bfa2fc85d8dd' 
  AND token = 'cim0eFNSC35I6i82SKLfEzOggTy+SYEOGMckcXXtdm8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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