SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b247b64c78f666bbc3daad081b5f3475ff98e1ad0136cede355145b37da98a63' 
  AND token = 'iVqT2cZAvLX5Opw0oIM6gy/pT/RKunAiwsTW2pNnxFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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