SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc7428b16ebc002ba37a0cf277e974b21f6bfcd2b5450fc7344dcd8334675a03' 
  AND token = 'kN4tHjgii1YeGxCsjb7cKWZOWcmTKh42DhSRR4Npiqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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