SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c3ec161bc531ff3727b1c29fe499201da760f6af87c7aade1a74cc600b84a358' 
  AND token = 'OzV+GcCGMQZX36g5gsyv1xkRX0e2+c75FCqXWF+LLvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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