SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '531b8ea0b74990063aadbb16cfba6fe6203755d17fffb8a88a7485ab86438403' 
  AND token = 'wHX7+9hHKvwFYlxjPSJ/qtyoW1e2KukjszxkHLUUSb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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