SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '32ccbe585ffdb667e06713aa00686ce5070075869e49d48e88792c2aebd5a843' 
  AND token = 'GNFrsvf/hNdzzPDh9lo3qvWAfUDVHK5WNK/18Z/MPDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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