SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a92e1172baa59c3cdca18a5fe0019398f89010ede896379f092c1637ca24f7c1' 
  AND token = 'IhU2fc6qgVmqTxyQk+Fkgw5VkMH+BQt6PeiZzqhI/lY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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