SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3d6666bb707f5274712e53c1dd337d3830514595477aa7652353732d499754a' 
  AND token = 'fbWZx8T5BtbdUjWeyE9S9DqVXOQS2jrNUMPx32bawgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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