SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e23e000f697348cd5ced2de5dce1dfd353566b45e705a004f374ea215346334' 
  AND token = 'Xaftzn3P17UsLvvmOQjTQb+8cwgPwiGWsVPfIARLPGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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