SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '363cbfc2e9217c55afa55ab28ff6e0b3876d943578dc8b0ba27eb2506723cac4' 
  AND token = 'CzLy+yJKtqdhIupd2uUgujHaj5eESmN0VQy9KGJ/++I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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