SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ba8c3d638b2cd121eba7d1672c47af082fa14ec9982adc834e5430d48962676' 
  AND token = 'HDCQua95btVvEbKwpZBvKH+q1U7KeMqkeJihpKGT7NI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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