SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc4a82682f17cd8659456e0805f1708acd937192195d3fead79f90272d0d11f4' 
  AND token = '4bnJ61MvkhkVQCLp9pa/rAlOg5QjojyawgFyBhw+8iM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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