SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76863f6b8ae9f13e067576096125211a46019282f07cab35ffca320595fd7c03' 
  AND token = 'NCtocbQmzTauKQKk5+xKCleC0awaOkdvmYKorQAIgL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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