SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4e5ed2c8a6faf05050ad5ec96449c33484b4b19847b67edaf8a9c3d6ca2216c' 
  AND token = 'oH7PzJZ1W1TfFG+G/WP9XH4eKInpJUdhMVeGhLr/cvs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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