SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e0025c31634e9503fcef0039e9d2c15eca7b9caf3b85940aeba6b6265556bb3' 
  AND token = 'BPfFWJzm+9kWi8zQ+WUHciZBxNaKfcqBa55JlxCZrDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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