SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b03a08111df5f2e49d3ea86ba04baef7177bbfe41bedd39f5a8d8fa4e4f91b02' 
  AND token = 'aZKE+3TwHf446jN5nECJ8XwqM9j87lrhGC2EWRrWsN4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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