SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '448978133200a96d2ad642fad34a3e1b28680270f1c0e84e895d1360625cf2c5' 
  AND token = 'VkqDhrlGnc9L9vB/wkB+7nz2ivrESMMjZiUttNXTsKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}